The machine safety user meeting + exhibition at the Vogel Convention Center in Würzburg, southern Germany, on 30 September 2015 provides information on ground-breaking machine safety issues. At the conference, Frank Schmidt, head of norms, committees and association work at Schmersal, will speak on evaluating fault masking for series connection of locking systems with potential-free contacts and the technical ISO/TR 24119 (E) regulations.
Series connections for locking systems are not uncommon on machines. It should be noted that, in the event of a fault with the wiring or the locking system, a fault recognised by a downstream control component can be ‘overwritten’ by opening and closing another locking system. This can result in a dangerous situation for the machine if another fault occurs. This effect is known as “fault masking in series connections”. Standards covering safety considerations for controllers, such as EN ISO 13849-1 and IEC 62061 do not go into the subject of fault masking in series connections.
Chapter 8.6 of standard ISO 14119 on “Safety of machines - locking systems in conjunction with isolating safety devices” describes the “logical series connection of locking systems” and refers to technical regulations ISO/TR 24119 which cover the logical series connection of systems. ISO/TR 24119 was drawn up by technical committee ISO/TC 199 (”Safety of machines” project) but is currently in the draft phase and not yet generally available.
Frank Schmidt talks about fault masking and explains ISO/TR 24119. The speaker will be focussing on the approaches to determining diagnostic coverage levels described in the new rules.
Frank Schmidt’s talk is scheduled for 13:00 on 30/09/2015 (Practical forum I)
Register at: http://bit.ly/1gT4oxd
Location: VCC Vogel Convention Center, Max-Planck-Str. 7/9, D-97082 Würzburg